>>3914150I do it all the time. Feels good man.
>>3913933This. MB-20 with lithium batteries gives you the smallest weight possible.
Only downside I see is that there is no hope to repair anything anymore in case the electronics stop working. Also watch out for LCD "bleed". Sooner or later they all stop working. Especially when the camera was stored in hot climates.
Bonus level is getting the waist-level finder for the F4! Grab it when you see it for cheap.