LS/VTEC Questions

I have read the articles stating the evils of the LS/VTEC and B20/VTEC hybrids. However I still have some questions. Hopefully some of you can help. I know of the longer stroke problem with the stock LS hardware. However, could this problem be remedied with aftermarket crank, rods, pistons, etc. I guess what I am really asking is, what is the difference between the B18A/B blocks, and the B18C blocks? Is there one? Would a crank designed for a B18C work with the B18A/B?
Thanks!