The hard part will be trying to find somewhere that sells an Easy Out or Extractor drill bit in only the size you need. Might be easier to ask a machine or engineering shop to do it for you (simple job - if they could be bothered) or suck it up and get a set for yourself (worthwhile if your a petrol head).
They’re not really exotic … most old school hardware’s should have an M3 x 0.5mm screw (phillips or flat), small springs to suit and you should be able to use the domed/serrated end caps from other sets to make 'em complete.
@ Jase: don’t worry if it fuck’s up and stays in there. Just grind out what’s left on the inside of the dropout and run without them. I do on a few frames without any issue’s but be warned that not all frames are so perfectly made that the wheel will sit in the right position without them (hence the reason for dropout screws on horizontal frames - to hide that the dropouts/stays aren’t exactly the same length/position). If that’s an issue then a few swipes of a suitable sized round file should match them up so the wheel sits straight
yeh, after i calmed down a bit, ive realised the few mm difference isnt really going to phase me, so ill just put the other side in and ride it, it really isnt that big of an issue in the greater scheme of things.
I had a frame with this issue, ended up drilling it out with a small drill bit, then ran a tap through the hole to clean out what was left in the threads. Worked perfect. There is potential for disaster as I think the screws are harder then the dropout itself, so the drill will want to wonder… But as long as you keep it straight there’s no prob.
But yea, if your not confident then the local frame builder would be the best bet
I know you already tried pliers but like alexb52 said, try again with needle nose grips. I had the same problem once only it was bent as well as seized, but after about a half hour of painfully slow twisting it eventually came free with no damage to the thread.