WSGF member Thebutcher has posted an interesting thread here outlining a possible open source future for SoftTH. If you're not familiar with SoftTH, it is a software multi-monitor solution that dates back to the days of the Matrox TripleHead2Go (TH2Go). Hence the name "SoftTH" (Software TripleHead). It was originally a software solution that allowed gamers to enjoy multi-monitor without the pricey investment of a TripleHead2Go.
Fast forward a few years, and AMD and NVIDIA both offer native hardware solutions for multi-monitor. However, SoftTH still offers one key unique feature - it allows for "non standard" configurations beyond 3x1 with identical monitors. SoftTH is known specifically for it's support for "PLP" (Portrait-Landscape-Portrait), which many users with a 20" - 30" - 20" configuration. All three monitors are 1200px tall, with the horizontal resolutions being 1200-2560-1200 pixels. It also allows for 1+3 configurations, and for all three monitors to be included in the gaming desktop. In fact, SofTH can support basically any configuration of monitors you can throw at it.
The one downside is that it only supports DX9, which is a little long in the tooth now. Thebutcher has broached the idea of making SoftTH open source, so that the WSGF and SoftTH communities can support the future development. He has posted a
forum thread outlining this idea. If you are interested in supporting this effort, please hit up the source link and reply to Thebutcher.