I have a jersey at home (a Zambro one at that). And while I see the appeal of it, at the same time there's something oddly strange to me about the idea of fans coming to a stadium dressed up like players. Sort of like the people who dress up like Klingons to see the latest
Star Trek movie. Or perhaps even more strange, going to Disney On Ice in a giant Goofy costume.
The times I've been to Juve matches, I wore a Juve scarf (once at the delle Alpi, once at the Stadio Comunale Artemio Franchi in Siena -- which, although it was historically Lippi's last match coaching Juve, the local fans couldn't tell one bianconeri from another

). That seemed to do the trick at a minimum.