It's funny that you bring this up, because I've been considering my next go-box project. This spring I plan on building a very small camping trailer, and because of the size, I'd like to build a smaller go-box than my current one using the IC-7200, and HTX-252. Before I forget, the IC-7200 has much better filtering than the IC-718, and it's ready for the digital modes, just a simple USB A to B cable is needed, no interface box or other interface is required, it's essentially plug and play. I believe you would find that the IC-7200 receiver is like another generation ahead of the IC-718, especially for CW and digital modes. I've had both radios, and the 7200 is well worth the extra money; that's what I currently use as my primary base radio, and of course I have another one in a go-box.
Getting back to the go-box, I'm considering using a FT-817, because of its size, wide receive capability, and its power demand. I've already ordered a deep .50 cal. ammo box for the project, and it should be here later this week. I'll use some go-box components from
www.qsradio.com, including power pole connectors, meters, meter mounts, and a VHF antenna mount. Quicksilver radio offers complete VHF/UHF go-boxes, wiring harnesses, etc. I'm going to incorporate some of their concepts in my go-box, but hopefully I'll save some money too. SLA (sealed lead acid) batteries and mounts are also offered, but I've been looking at Hardened Power Systems QRP Ranger:
http://www.portableuniversalpower.com/our-products/qrp-ranger/ , which costs a lot more, but the battery pack is incredible, since it uses LiFePO4 cells, which can be drawn down 99% and not damage the battery. In fact, I'm probably going to use a LiFePO4 battery for the trailer, because they can be recharged 1000's of times, and they weigh much less than conventional batteries. There are mounts available for the FT-817, though it may end up being cheaper and more effective to construct my own. Because the FT-817 only transmits 5 watts, I can use a smaller tuner as well, so I'll be using a Z-match kit, which was ordered from China for less than $15.00. I've already constructed an end-fed zepp antenna for HF coverage(total cost around $40), and I'll use a simple quarter wave whip on VHF, since they're so broad banded. I already have a FT-817, and but I plan on purchasing a FT-817ND for the project, because I adhere to the two is one, one is none school.
I should note that qsradio.com mentions that the FT-817 will not fit in the ammo boxes which they offer, which is why I went with the deep .50 cal. box, it cost me hmmm $35 shipped. I'm guestimating a used FT-817 should be in the $500-600 range, according to past sold FT-817's on eBay. I figure another $120-150 in switches mounts, and connectors. The battery will be $50-300 depending upon what I end up purchasing. I'm guessing the whole thing could be done on the cheap for $750, but realistically, if I do it the way I want it, it'll be closer to $1000.
So there you go... some ideas to consider. I look at go-boxes as communications centers, but I also like to incorporate the ability to charge other items, like cell phones, Ipads, etc., so I typically plan on having a large enough battery/solar system to cover the additional loads. The FT-817 is a relatively minor power load, because it only transmits 5 watts, that can be a disadvantage on SSB, though not so much on CW and the digital modes. A smaller solar array of 30-50 watts should easily be able to handle the FT-817, and other loads like cellphones, Ipads, etc. I'm not intimately familiar with the FT-897, but it is going to require a larger charging system, larger battery, larger tuner, etc. No matter which 100 watt transceiver you go with, weight of the radio and battery are going to be a factor. Using the FT-817 radio, and the QRP Ranger battery, the entire go-box should weigh much less that 10 lbs, and it covers HF/VHF/UHF. The negative factor in both the FT-817 and FT-897, if you have a major problem with the radio, then you will likely lose all communications(and I've already had that happen to mine). The nice thing about using the two Yaesu radios, less cables, wires, and microphones. Using the two Icoms, if you wish to cover VHF/UHF, you'll need to buy additional radios for those frequencies. If you add vhf/uhf radios, the overall cost goes up and so does the weight of the box.
I guess you need to prioritize which features are most important for you: frequency coverage, transmit power, weight, simplicity of assembly, simplicity of use, receiver selectivity, ease of adding digital modes, availability of components, battery size, charger size, and cost. You might want to create a chart and see which radios fit your needs and expectations.
As I get older, weight is becoming important, and I'm willing to pay to keep the weight down. Ease of use becomes important if others are going to be using the station. Determine which factors are most important for YOU! I find that planning and obtaining the components is half the fun of the project. Send pictures when you're finished!