Although signing a top SP'er costs more than a top closer, they seem more likely to not fail than RP'ers often do. I have no evidence to support this, and out last big pitcher signing, Price, did not work out all that greatly.
I know we want to avoid 5 or 6+ year deals, so I really would not be surprised, if we sign one or two of the older pitchers to a 2-3 year deals and use Houck in the pen.
Yes, Houck has great value as a starter, even if he continues to get yanked after the second time through a line-up, but getting starters who can go 6-7 takes a lot of stress off the pen.