I do, from first hand experience: we're developing insurance pro software, and also have an all in one hosted solution, where we handle everything for the customer (from storage to configuration to backup), we set up an IPsec link and they just connect via TS. The product, which has a codebase that organically evolved during 10 years (resulting in DWTF worthy stuff), solves a number of real problems for our customers and in spite of the warts and bugs, they do like the product. It's hosted on Windows machines, including Office and whatnot. The growing MS license costs are currently driving the hosting solution out of business. We know first hand that alternative solutions (like a hypothetic port to Linux) would have cleared enough money to hire two developers, and get rid of a dedicated MS sysadmin (so that makes three full-time engineer jobs). And we're not even talking about moving to a web-based solution, which would cost a fraction of that again (and we know that because we're developing and hosting web stuff too).