That would be sweet if they could resurrect a trolley line from central station across van buren up Grand all the way past 15th ave. That was basically already a historic streetcar line, just bring it back. Similar to how they brought back the 4th ave trolley in tucson.
EDIT: after doing a quick search on the historic tucson trolley (old pueblo trolley), it appears that was brought back from the dead for the 1985 100th anniversary of the university of arizona. Bringing back a trolley on grand avenue would have been a great way to celebrate the Arizona Centennial in 2012... maybe it's not too late.
EDIT2:
What if this was a streetcar line, and instead of just heading up Grand, it made a loop around NoDo (j/k - northern downtown). I know it would be impossible to cross the existing light rail line twice, but if there was a loop from central station, west on Van Buren, NW up Grand to 15th Ave, then east on Roosevelt all the way to 4th St, south on 4th St to Van Buren then west on Van Buren back to Central station... that would tie in all of the great parts of northern downtown. It would connect the Grand Ave art scene to the Roosevelt St art scene, connect the BioScience area to everything, connect the Sheraton to everything, and having a streetcar along Roosevelt from 4th St to 15th Ave (probably our most historic urban in-tact stretch of street) would be amazing. On First Fridays they could run the historic trolley cars and connect Grand with Roosevelt (two great areas, but relatively disconnected on First Fridays. The whole stretch would be just over 3 miles.