I got the urge to plug the holes on the frame where the swing arm pivots. The opening measures 1.25". Guess what, you can buy a pair of the exact size chassis plugs (Boo Boo Buttons) for less than $3 at your local hardware. A little Krylon and you're set.
Looks better than my "Stewarts" root bear bottle top. Maybe, but you can change your flavor as you wish.
I am going to print up a few of these tonight (I have a 3D printer) and put them on my TR after I prime and paint them...
The steering head plug is a tad bit looser than I wanted but they fit! I'm thinking of either putting in an o-ring groove in v2.0 or just use the ones I printed and putting on a thin bead of hot glue or silicone and letting it fully cure to proving a friction fit (and provide a water tight seal much like the oring would).
I can size the steering one up in makerware to fit, so no worries there. I'll test them out when I get home. If I may make a suggestion, hollow them out and add a couple slits around the base just like the OP's buttons. PLA and ABS should have enough flex so that you can oversize the plug by a mm or 2 and they'll snap in snuggly. I'll see if I can't throw them in Blender or SketchUp later and do that.