No experience with the Maggie Unitrac, other than reading a long standing good reputation, but one of the Sumiko Premier arms may be easier to find. There was an association between Sumiko and SOTA and those arms were a common match when they were new products. The first generation of those arms was the MMT. It was S shaped and offered a removable headshell. The later FT-3 and 4 had straight arm tubes and a fixed headshell.
I owned a SOTA Sapphire with the FT-3 which seemed to offer very good performance per dollar. And yes, the FT-3 included a threaded VTA adjustment that was easy to use. The manual said it could be done "on the fly" although I never tried that. You should be able to find a nice example for under $300.
The AQ arms were similar (sourced from same manufacturer) but I don't have any experience with them.
