Well, since you're sharing some connection with Guild now, and I'm betting they're not going to be making a Starfire II bass with Dark Stars in the foreseeable future...
Well, when I think Hamer, having come of age musically when Cheap Trick was still playing the Red Lion Inn in Bloomington while working the "Blytham circuit", I think of really nice Gibson-style instruments that are refined and built consistently well. Shortly after I quit retail music the store I'd managed started carrying Hamers, and the one I was most taken with was the Sunburst. Now a double-cut Les Paul style body is for the most part utterly useless for a bass player. There's a reason that horn has to be out there at the 12th fret.
So, take that kind of inspiration that led from a Les Paul to the Sunburst, and apply it to a couple of classic basses. I loved my ('90's) Cruise bass, and while I fully understand the "no Jazz bass clones" directive, you could still take that classic Icon and do what Paul and Jol did to the Les Paul to it.
The other obvious one is to make a really nice, but balance Thunderbird. It doesn't have to really LOOK that much like one, but have the essentials- the mahogany neck-through construction, those particularly peculiar Thunderbird PUPs, but have solid and reliable bridge desing (Hipshot, cough-cough), light-weight tuning machines, and the usual Hamer obsessive attention to details like shielding, high-quality pots, impeccable fret-work, etc. Again, dont' try to make it LOOK like a T-Bird so much (that's an ergonomic disaster for most players), but have it WORK like a T-Bird.
John