BL said:
If you feel comfortable, and he is a close enough friend, ask him to borrow it over a weekend when you are shooting MMA or sports when he's not shooting 2nd.
This will likely answer most of your questions. Something tells me 6fps from the 5D will be sufficient - getting keepers has more to do with technique (e.g. timing and anticipation) in action, imho anyway. 1Dx just takes spray and pray to a whole new level.
he wont loan anything out.. I needed a 70-200 f2.8 for a work event and I hinted needing to find one to borrow. later that day we were talking about something and he said.. yeah that is why I dont loan anything out to ANYONE....
also spray and pray... i do fine with my 3.4 a sec... I got ok timing.. anticipation.. I did one street hockey and got EVERY goal in the net... think it was like 6-4... what I want out of the spray is simple... something I have wanted to do and cant do with my t2i...
see an anticipated goal from the goalie... or dive save...
zoom out a bit for full frame I want... start the ... RATTTAAA TAAAT TTAAAAT TAAAAAT....
then at home take say 8 or so.... layer them in Photoshop and have that beautiful pic showing all motion where starting point is faint all the way to the dive save that is not faint at all...
same as baseball... get the pitcher winding up and throwing.... ball in air down the plate line.. then batter hitting...
a lot of work on that one but would be cool....