I'm using the stainlessbrewing.com 50 footer also. I've been getting about two degrees/minute at the HEX output on the evaluation rig and expect to do a little better with the same burner and HLT on the new brewstand because I'll mount the burner higher. Of course, it takes additional time to run the entire wort through the HEX. I expect the directly heated MLT on the new stand to be much quicker because of the reduced water mass to be heated and because there'll be no HEX delay. I expect to still use the HERMS mode most of the time because it is fast enough for most of what I do. My primary reason for the MLT burner is to heat the strike water separately while the HLT is heating up to mash temps.
No photos yet, as it is still a work in progress. I have the new MLT and all the burners, solenoid valves, pumps, and hardware for the stand. I cut the new control panel today and have most of the components mounted. I expect to have it completed and wired this weekend. Then I will be stalled, as the stainless brewstand I ordered in October from brewershardware.com has been predicted for "next week" every week since. I haven't been too upset because I wasn't ready anyway, but next week I will be ready and inconvenienced.