Digital BW, The Print

Perhaps this is a bit off topic of the group, but you are an 
experienced lot and I cant resist asking for some advice. Neither 
could I find anything on this topic by searching group posts so I am 
asking here. 

I am looking for scanners both for 35mm and 6x6 B&W negatives. Nikon 
Coolscan 8000/9000 and the similar Minolta Multi Pro is just too 
expensive for me. I am planning to print up to A3+ from 35mm and 
20"x20" or even larger from 6x6.
 
I suspect the Epson 4990 flatbed or Canon Canoscan 9950F will do for 
6x6, but not for 35mm.  Perhaps the solution is a second hand 35mm 
film scanner and one of those flatbeds for 6x6? 

But which filmscanner? Nikon Coolscan V or LS-50, Minolta scan dual 
IV or 5400/5400II - or what?

I read something about different light source in filmscanners,- that 
LED light in the Nikonscanners (and 5400II) makes the filmgrain more 
pronounced. 

I would be very happy if the members of this group could share some 
experiences with me.