The Goldberg Tiger 60 is available as either an ARF or a kit, I don't believe the plans are available seperately. You'd have to contact Lanier to find out.

http://www2.towerhobbies.com/cgi-bin...?&I=LXDJD4&P=7

Another kit that would be a wonderful match for your O.S. Max .61 Fx would be the BTE Venture. The designer of the original Sig Four Star later designed the Venture as sort of a "Four Star V2.0" with several improvements over the original:

http://www.btemodels.com/venture.html

You should be absolutely thrilled with either one of these fantastic designs.