Here's what I came up with. It's *mostly* scientific, but cheated on the lower ends and the higher ends. The idea is to find the 'average' on any set of dice and then compare it to find the appropriate (or approximate) BOL damage. Any comments, criticisms or corrections are greatly appreciated (it also assumes that the figures above are correct!). Sorry about the formatting!

Oh crap. The formatting is unreadable. Oh well. Here's the common damage conversion. I have MANY other dice combinations converted as well.
D&D COMMON DAMAGE=BOL DAMAGE
1d3=1d3
1d4=1d6L
1d6=1d6
1d8=1d6H
2d4=1d6H
1d10=1d6+1
1d12=1d6+2=
2d6=1d6+3
2d8=2d6+1
2d10=3d6