I haven't really tried silk knickers before, but I would be worried about getting lube on silk due to the nature of the fabric and how it can very easily stain. I have silk pillow cases (two 100% silk) and I have gotten lube and similar fluids onto them before, they are now ruined, and the marking won't even wash out.
As for silk gloves, ebay is a good place. I've picked up a few pairs of vintage 100% silk glove, all unopened, for only a few pounds. It's handy to know your glove size when looking for a nice pair of glove, you can easily google a chart which tells you how to measure.
I would recommend the satin knickers from the new starline range: http://www.lovehoney.co.uk/product.cfm?p=21896 http://www.lovehoney.co.uk/product.cfm?p=21897
Ok I know it's not silk, but this is the softest and most devine satin I've stroked. I have the bloomers and love the how soft the ribbon tie-up back feels. Satin is a weave of fabric, one side is a textured and the other smooth and glossy. It can also be made out of silk, though most products are made from nylon of polyester.
There's a few products that are made from silk on Lh. Though only one is for us girls: http://www.lovehoney.co.uk/product.cfm?p=18412
There's loads for men though, which I guess is worth considering: http://search.lovehoney.co.uk/search?p=Q&lbc=lovehoney&uid=482536448&ts=custom&w=silk&af=sub:briefspouches%20cat:underwearformen%20dept:lingerieclothing&isort=score&method=and&view=list
There's a few sites I know that sell silk lingerie, but they are very expensive. I'm not sure if I can link them or not. Though how much would you consider spending?
Hope this helps.