Just to put it out there:
While the whole "tow the Me-163 to altitude" isn't really doable in a pure form, it's easy enough to fake in the FMB:
Just airstart your 163 behind the towing plane at altitude, with throttle fully retarded for "realism" (i.e., not starting at full rocket power)
Yeah, it isn't perfect, but some of the best gimmicks that have been put in Il-2 missions are little more than this, creative tricks.
Sure, it's stating the obvious, but it is an option for mission makers in lieu of glider code additions.
As an appendum, the Jagerfaust as an added loadout for the Me-163 would be a great idea, in all honesty....