Hi. I get asked to do this very regularly, as will any general carpenter with a machine shop. Take a sample of skirting along to your nearest friendly carpenter and ask him if he can run up the required lengths. If he can't, he'll certainly know someone who can.
Few warnings. Firstly if it really is non standard (unlikely), you might be in for a hefty setup charge. The cutters for the machine we use may need to be purchased or even manufactured specially. (Don't worry, they're not that expensive Â£50 - Â£100ish) Secondly it does take a bit of time to set the kit up, so if it is for just a few mtrs be prepared either to pay for the privilege, or wait until the shop has some otherwise dead time to fit it in.
If you cant see the skirting on the rack at a builders centre, it means your going to have to have it specially made at a joiners workshop. If it is a 1930s style house it could be called lambs tongue. Ask to see a piece to confirm. Take an offcut with you and ask for a price, The number for a joinery firm can be found in your yellow pages. Hope this helps, Leo.