My proposal:
1) Allow users to run external applications from SL via command-line or shortcuts. This option would only be accessible from the menu, to avoid malicious script issues. ALTERNATE IDEA: allow SL to "capture" the window of a currently running application.
2) Display the application in a window, much the same as the scripting window (or any other window for that matter). No "prim displays," nothing fancy, just a simple interface to another application. Maybe you could use some partial transparency, but that would just be gravy.
Doing this would let people blog, work on web pages, check email and IMs, code, make graphics in Photoshop, and so on. It would also encourage people like me to buy land; I don't care about having a house in SL, but if I could work in-world then I would definitely want to build an SL "studio."
A future idea would be to allow others to see your window; perhaps you could "detach" windows from the display and move them around like an object (within a limited range of course).
I hope that other people find this idea useful. As I said, the benefits run both ways... we can stay in-world more often, and Linden Labs would get more land money.
