I have now received in the post the Pro-Tec 'Drop-in' elbow pads I ordered from Blackleaf.com [http://www.blackleaf.com/Protec-Safety-Equipment-Pro-tec-Drop-In-Elbow-Pad-Black/blp10406.htm
] for the princely sum of £31.45 (free P&P).
It took me bloody ages to find a set of elbow pads that definitely had a sleeve as well as straps - I recall from my teenage years that the nylon strap jobs are usually uncomfortable and ill-fitting - and these seem to be just the ticket. They come in the ubiquitous 'HEMA black' colour, and are a good fit. As a nice touch, the hard cups are replaceable, and attach by some pretty ferocious velcro - I think a solid blow with a weapon that caught them under the edge could take them off, so I would only recommend wearing them underneath something.
In a fit of productivity, I cut the extra flappy bit off my longer-model Spes Vectirs since it was now completely unnecessary, so they now end where the skate pads begin. Ideal! Interestingly, this also let me see 'inside' the Spes pads, which are layered as follows:
1. (Next to the skin) Cotton lining
2. About 5mm of reconsituted chopped-up fabric padding
3. Hard multi-layered plastic plate
4. Cotton lining
5. Durable synthetic fabric exterior
I found that wearing both under an AP jacket meant that it was impossible to bend the arms much more than 90 degrees. However, with the elbow pads under and the Vectirs over, there was not much difference in army mobility to just wearing the AP on its own, and hard protection coverage was practically the same as with the longer flappy Vectir guard. Wearing the Vectirs over the top isn't as smart (i.e. aesthetically pleasing) in my opinion, but it is more in line with 'principles' (if you can call them that) of protective layering - rigid over, padding under.
Have to go and do some tutoring now - pictures to follow later today!