The following Marvell devices can sometimes be found on ebay for reasonable prices and are actually OEMed from GlobalScale Technologies, PogoPlug or Ionics:
Some example ebay listings:
http://www.ebay.com/itm/APPNETA-M22-WD-NETWORK-MONITOR-W-PSU-POWER-PLUG-/201937170030?hash=item2f0464ae6e:g:oy8AAOSwPh5ZKO35 -- DreamPlug
http://www.ebay.com/itm/FF3-Appneta-M20-pathview-micro-appliance-/152679879968?hash=item238c6e1520:g:naYAAOSwFV9XxfKm -- SheevaPlug
- AppNeta Pathview M20 is actually an OEM GlobalScale SheevaPlug
- AppNeta Pathview M22 is actually an OEM GlobalScale DreamPlug
- Smartenit Harmony P2 is actually an OEM Pogoplug Mobile
- Ihiji Invision INV-APP-500 is actually an OEM Ionics Nimbus which according to https://www.cyrius.com/debian/kirkwood/sheevaplug/plugs/ is compatible with the original SheevaPlug
Some example ebay listings:
http://www.ebay.com/itm/APPNETA-M22-WD-NETWORK-MONITOR-W-PSU-POWER-PLUG-/201937170030?hash=item2f0464ae6e:g:oy8AAOSwPh5ZKO35 -- DreamPlug
http://www.ebay.com/itm/FF3-Appneta-M20-pathview-micro-appliance-/152679879968?hash=item238c6e1520:g:naYAAOSwFV9XxfKm -- SheevaPlug