[GeeTwo]

At $325 a pop, and building two robots, we're looking at $2k for swerve or crab just for gearboxes and wheels. Unless we were reprising Tumbleweed, this would probably blow our budget.

We're with MrForbes above - we did our own chassis for our second and third year, but when we forgot to opt out last year, we realized just how versatile the 2014+ KoP chassis is. We opted out this year, but have ordered two AM14U2s (2015 chassis) and these are 95%+ likely to be the main part of our chassis this year. By using some Vex 1"x1" c-channel and a drill with a 3/16" bit, it is easy enough to use KoP below and VersaFrame above; that's our most likely construction for 2016.

WCD will buy you another inch or two of track width for the same robot width, but this has not been a major consideration in our last several robot designs. If it does prove to be one, we can always rearrange the wheels and sprockets on those shafts, and even bring the "outer plate" inside of the wheel if it seems necessary to do what I'm going to call a Gulf Coast drive. (and that's just the beginning of some of the weird things you can adapt the KoP to do.)

As far as COTS causing a style to become (or cease to be) dominant, I think that the COTS availability of omni and mecanum wheels has done more to open up the possibilities of something other than drop-center to teams with a $1k+ robot budget than anything else.