We plan to bring Survex to version 1.0, and then start to develop version 2 (codenamed Spud). Spud will evolve out of Survex 1.0 - the GUI framework is likely to be based on aven, with the printer drivers and other utility programs being pulled in and integrated into the menus.
Aven is built on wxWindows, which means that can easily support Unix and Microsoft Windows. Mac support is also possible if anyone with Mac expertise is interesting in porting Spud. There's no MSDOS support in wxWindows at present, though it may be added. Support for RISC OS is unlikely.
More information on our plans for Spud is on the web site.