Usually in 208 ltr barrels bud. I've got direct accounts with Mobil, Castrol, Total, Morris, Rock Oil and Motul via Witham Oil and Paints.Sounds very much like you do exactly what I do. Pick a *w40 oil that meets ACEA C3 with a few approvals and with a few minor exeptions just use it in everything.
What sort of quanitity are you intending on purchasing? Might be worth speaking to Opie Oils or Broughton Lubricants about your requirements and see what they offer.
I've also had good experiences with Millers Oils but they're a bt stingey with approvals.
We stock LL3 5w-30 - 208ltr
0w-30 acea C2 (for SsangYong, PSA and Ford - 208ltr
5w-40 502.00 505.01 - 208ltr
Genuine VW Eco screenwash - 199ltr
The rest I keep in small pack in Texaco Havoline.