When I replaced the slave cylinder on my truck it was with the OE part from Burt. IIRC it was price competitive with aftermarket (I want to say about $45). Sometimes you get genuine Aisin parts from NAPA and IPW, though, so it's probably worth checking.
Getting at it is a PITA, but it's not the worst job ever. I wouldn't rule out a hard line, they can rust, too. I have one of those power bleeders that might be handy pressurizing the system to look for a leak. Not sure how I'd get it to you any time soon, tho.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna