The LS-50 was the "Coolscan V" in the US. It's a slightly down-market LS-5000, but I'm not sure exactly what the differences are, beyond that it doesn't take the roll feeder (SA-30).
I tested the older Plustek 7500i, and it's a decent scanner. It can achieve ~4000 DPI in 7200DPI mode (but then you have to down-sample, of course). Bundled with SilverFast it it probably makes a decent scanner. But it doesn't have AF, nor multi-sampling (I believe the LS-50 does, though it's not critical for C-41 due to relatively low densities). Each frame has to be advanced individually, vs. 6-frame strips with the SA-21 on the Nikon. Plustek doesn't have ICE, per se, but it does support SilverFast's iSRD, which is an IR-based scratch and dust removal.
It's kind of a toss-up between the 2...different pluses and minuses. Sorry I can't make a firm recommendation, though.
You said something about a local lab? What about getting them scanned at 2000 DPI on a Noritsu or Frontier minilab? This is what Costco (membership-discount store) or Target (discount department store) around here does at the time of development...not sure if they'll do it after the fact. My local lab (Portland, OR USA) charges $7.50 a roll (if they're uncut) for this service, either at development or after. Some may offer 4000 DPI scanning...2000 DPI isn't quite enough for an 8x12, but certainly enough for web use or smaller prints.
Good luck...
--Greg