I haven't seen an aftermarket 14"x4.5" wheel either. Personally, a 14" x 5" rim would be a good choice for a Mirage, but most aftermarket rims start @ 6" wide & up. Some
I have 14"x4.5" (145-175 mm), 14"x5" (155-185 mm), & 14"x5.5" (165-195 mm) steel rims for my Mirage.
Personally, I am content with the current 165/65r14 offerings in both all-season, all-weather, & winter tires these days. Dunlop, Bridgestone, Federal, Nexen, Kumho, Falken, Vredestein, & Nokian are all marketing 165/65r14 tires in the States. It's not the great selection of Europe & other places, but it's better than it had been.
175/65r14 (23") & 185/60r14 (22.7") are good options for those wanting a slightly wider tire, & they would fit just perfectly fine on any 14"x6" or 5" or 5.5" wide wheels.