(However long this post is, I think it's worth reading haha)...
elecTRONica is not going to be a permanent thing. I wish it was, but when I went there, it was pretty obvious that everything set up was very temporary, and when you visit, you'll be able to see it too. I wish it was. However, there is a rumor going around about a Tron ride being built in Tomorrowland. They are clearing out a huge space that used to have a ride in it and putting it off for construction - so we shall see. They keep extending the stay of elecTRONica though.. so..
smiles all around. I hear they're extending it until the end of October, so it should still all be there when you visit, including the merch..
Merchandise in Disney: IT IS ALL OVER. When I went to downtown Disney, I went into a store called D Street (I think? There is another one called TrenD, but I'm pretty sure it was D Street).. Near the back of the store, they had a whole Tron section filled with a couple varieties of hats, several different versions of jackets and hoodies, a Tron dress for girls, Tron tank tops, loads of Tron t-shirts, disks, toy cycles, both DVD's, both CD's.. it was pretty amazing. I sat there in awe for some time before a couple guys came over and were like "Flynn Lives!" haha..I about died of happiness.
Later, in California Adventures, They have a huge store that you can't miss when leaving/going to elecTRONica.. when I was there (at the end of April) they had two of their store windows lit up and full of Tron merch. When I went in there, they had a whole middle section with Tron items...amaaazzinggg...I bought a glow in the dark Tron shirt from that shop haha. (Didn't know it glowed until later).
When you first walk into California Adventures, there is a store DIRECTLY on your right that has Tron merch in there too, but it's mostly just the toys, not clothing or anything. (If you're leaving Cal. A. it's on your left near the Zephyr (spelling?) place where they serve ice cream and stuff.)
Then AT elecTRONica, as someone mentioned, they have the kiosk with a couple Tron things there. I remember they had collector Disney Tron pins (the ones that people put on their landyards)..I bought both of those.. then I remember them having the light cycle toys and disks at that kiosk and a couple t-shirts as well.
You can also find both Tron DVD's and CD's (the Daft Punk one and the Remix edition) in Disney at a very small book/movie store they have on Main Street U.S.A.
However, if you are planning on buying Tron merch, be aware that it IS expensive. I was surprised. I think I remember the dress I mentioned being about $60-65. Some of the really amazing jackets I was looking at were about $85, and some pants and t-shirts were in the $55 range. That may not be spendy to some, but it was for me.. I'm glad I got out of Disney with two pins and a t-shirt.
If you're looking for Tron merch, and are heading to Disney, like I think one of you mentioned, definitely save up some money for it..because you aren't going to find this stuff anywhere else, and I wish I had saved more spending money for that reason. It was pretty freakin cool. I'm kind of picky about my clothing..Like they had a really cool pull-over Tron hoodie there..but instead of it just saying Tron, it said elecTRONica..so it kept me from purchasing it.. (small things like that are what i'm picky about)..but they DO have really cool stuff there...it's all over
And for those of you who have looked at some of the stuff in Hot Topic, I went to look at what merch they had and found a pretty cool Tron shirt on sale there, so I ended up getting it (on sale for $16.. :/) And it's really comfy and I'm definitely glad I bought it. So if any of you were looking at that..just throwing that out there that it's worth the purchase.