... I'd like to throw in a mention to the German Original Series/Next Generation crossover feature 'Das Vermachtnis' (The Legacy), as featured in Denise Crosby's Trekkies 2 documentary. It cold have been just incredible!
It featured well-tailored uniforms, Q, Klingons, plus great replicas of the original/-D bridge; TNG Shuttle and Klingon bridge. Picard looked younger but with hair, but that didn't matter. The whole thing just felt RIGHT. 'Vulcan' Willi Wiegand, a well-known Spock imperonator in Germany who was in charge of promotion, regularly corrosponded with fans online and provided updates.
There's a preview of what might have been at 2:53. I would have watched the entire thing without subtitles/dubbing, even though I don't know German. Apparantly the whole thing was shot, however Director Christoph Hees decided in post-production it was 'God's will' that the thing would never be completed. Such a damn pity.
Hopefully all the footage still exists so someday it could be edited/SFX etc. Hopefully. I tried emailing Christoph on Willi's advice but alas no reply.
My understanding of this is that the guys involved got married and had kids, and decided that was going to be their priority. I do think it could be finished one day, but we are looking at a Yorktown II type timeline.