Probably folks who know more than me will chime in, but the only one I'm aware of is this: http://theadventuresoflactatinggirl.com/
(I'm not positive she's American, but signs point to it), and her daughter is older now. You might try asking at the La Leche League forums (llli.org); they have a Solids subforum which is where I heard about BLW, but it's not very active. I've seen a few articles about BLW here and there (I particularly like this one
that someone posted here but I think originates on a US blog), but not many.
Based on representation on this forum, I would say that BLW is basically unheard of in the US. I think I'm the only American posting regularly here right now and I only recently barged in here and started making a nuisance of myself.
I'm sure many more Americans lurk, but I would still say that BLW is even less common here than in the UK.