try www.northmusic.co.uk

DX100 slider caps are avaialble from North Music Ltd - see http://stores.ebay.co.uk/North-Music-Ltd or email richard@northmusic.co.uk

Hi - we currently holds these keys in stock - link below...
http://www.ebay.co.uk/itm/Yamaha-QS300- ... 76c31b7936

Sorry - gave the wrong link (for a DX11). Drop me a line and I can send you a DX100 slider cap (as a free sample). It's not 100% identical as it is missing the white line, but otherwise fine.

try this site:
http://www.ebay.co.uk/itm/Yamaha-DX-11- ... _500wt_969

I have this type in stock...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _500wt_969

for spare Roland keys try...
http://www.ebay.co.uk/itm/Roland-Juno-6 ... _500wt_969

For vintage sythesizer keys (Roland, Korg etc) try:

http://stores.ebay.co.uk/North-Music-Ltd