Placed an order for some various bits and pieces with Gremlin Solutions a few days ago. They're probably not the cheapest around but they have a huge range of stock and the delivery was super fast. A couple of days only from the UK to Ireland.
For anyone interested, this is what I picked up:
JPac USB Version
Seimitsu LS-32-02 * 2 (White ball tops included)
Sanwa OBSF-24 Orange * 1
Sanwa OBSF-24 White * 2
Sanwa OBSF-30 Green * 6
Sanwa OBSF-30 Orange * 6
Sanwa LB-35 Green * 1
Sanwa LB-35 Orange * 1
The one player panel came with a non stock yellow colour Start button. I bought a single OBSF-24 in Orange to return to panel to its intended glory.