Fiber 10Gb is very cheap. NICs and SFPs from Ebay, fibre from FS.com in whatever length you want. I got a plenum rated 100 ft 4 pair cable from FS.com for $100

Fiber 10Gb is very cheap. NICs and SFPs from Ebay, fibre from FS.com in whatever length you want. I got a plenum rated 100 ft 4 pair cable from FS.com for $100 or so, and it was only that expensive for the plenum rating as it runs through my cold air returns.