The other day when I was working on my robot (buildig with 2.75" omnis) I thought “I could easily make this chassis work with mecanums” but I cant fit 4" Mecanums in to the robot chassis. After that I thought “What if vex sold 2.75” Mecanums?", I think that these would be really cool and very useful to soem teams
Untill they are sold by vex, you could always try to machine your own like some other teams have done
I considered that, but would rather speed time on more important things 
I would rather see some thinner mecanums then 2.75" ones. I find that the drive trains our team always ends up with are wider then they should be because we need to fit the mecanums and chain in there.
Just my .02
I agree. I think that If mecanums can still be 4" but if they are thinner and just have more roller wheels, VEX could have an omni-size wheel in thickness which would give much more room for robots.