Tamron making Fuji lenses (assuming for a moment that the rumor is correct) means Tamron working with Fuji to pull it of. The result can only be products that benefit both companies. Cooperation, not competition.
I bought my first Tamron lens in 1977, a 135 f2.8 adaptall in Fuji ST mount. I still have it and use it, works like a champ. I've used many Tamron zooms over the years, mostly from the SP line, my favorites are the 70-210 f3.5 and 35-80 f2.8-3.8. I used a 35-105 f2.8 Tamron SP on my Maxxum 9000 (auto focus) for years before selling the whole kit. My Canon 7D wears a Tamron 17-50 f2.8 VC, one of the sharpest lenses I have ever owned. A Tamron 90mm f2.5 adapted lens is my go to macro for my Fuji cameras. To say that I look forward to trying a Fuji-specific Tamron lens is a bit of an understatement!