Nice photos. But the limit comes from the gearing constraint of track bikes and conversions vs your low gear ratio.
At any rate, nice bike. Nice photos. What gearing are your running?
First picture: 36x20 on 29" wheels
Second picture: 42x17 on 700x35
Third: 34x19 on 29" wheels
The 29ers are geared same as a 2:1 26" mtb, the other bike is a Surly crosscheck conversion.