Cris - bump up final finals for 1/10th off road at major competitions was the normal format way back in the early 80's... so no, its not a nitro thing.
Lipos these days give the opportunity to open door to new experiences, why not embrace them you might like it.
Alex - in the nicest possible way, your being ever so short sighted. Any A final at any RC event should and generally is exciting. However the other finals in the electric classes, really dont come close in terms of a spectacle to that said A final. Ok, so you have had a go and you dont like it, thats your opinion. My opinion is, your wrong
You see that making the A final is your days target.. not winning the event. With no one directly into an A final, the best qualifying goal would be to make the semi final, which in a 2 sided bump format would be 16 racers (8 in each semi)... so the chances of making the maximum qualifying position is increased. Yes, i agree that if you break in the semi, you dont make the ultimate goal of being in the main, but equally, break in the main and you wont win either. Racing should be racing and getting it over the line in one bit is part of racing.
Its a different format that would be fun and during the finals, would create an interest in every single final for all attendees (well maybe not my misses).
As for charging, 2 packs of lipos would cover it no problem. You race and then bump, you put that pack on charge and put in another pack, while the other side of the format runs. You then race and bump again. At this point you swap batteries again. The first pack would have been on charge for around 15 minutes minimum, which would have pumped in 1000mah at least. I would think you could do 4-5 finals like that before a pack would run flat.