Well I'm probably one of the few other PPRuNers to have been to Lappeenranta. Mrs WHBM
was at university there a while ago, but comes from St Petersburg. I've flown into there with Golden Air on their Saab 340 (big runway, little terminal), and I've even had lost baggage there (35 minute connection at Helsinki from London; it came on the next flight and the handling agent drove the bag over over to my hotel personally in his car later that evening, on his way home). Even looked at renting a PA-28 from the flying club there for a jolly. Oh, and I go into St Petersburg from London a couple of times a year.
Yes there is a huge demand for Ryanair FROM St Petersburg. There are friends of the aforementioned Mrs WHBM
who are going by bus from St Petersburg to Tampere (takes a day each way) to get on Ryanair for London or Hahn. There are also plenty of Russians who go to Helsinki to get holiday IT charters and other flights.
Lappeenranta is right on the border, as you realise by the various Russian-language roadsigns about town. And it has that runway. Main business is a huge paper and pulp mill that actually imports much of its raw material from Russia nowadays (no tree-hugging environmentalists over there). Regular coaches run to St Pete, journey of about 3 hours.
It's always struck me Lap would make an ideal Ryanair point. Key destinations would be Skavsta for Stockholm, London, Beauvais for Paris, and somewhere in Germany, maybe Lubeck. St Petersburg must be the most underserved city of size (it's 5m population) in Europe for air service, far less than Moscow even. Low costs are not coming to St Petersburg Pulkovo airport any time soon, Lap is the next best thing. There would be quite a market for Russians Ryan-hopping round Europe, many of them seem to do this already through Britain, Sweden, France, etc.
Visas are not such a bad issue as many St Petersburgers have Finnish ones, and with Schengen if you are going to mainstream Europe you are covered for Finland. More problematical are the arrangements for independent foreigners going into Russia, but the Russians are looking very closely at Ukraine, which abolished visas (or most of the difficulty anyway) earlier this year and has seen a pleasing influx of visitors, especially Euro-spending ones.
St Petersburg is a city of absolute world-class tourist attractions, and if it really got going on the international tourist circuit they could make huge income.