Any 8052 is fast enough. Midi is only a light job for an 8052 (derivative).
A pause between messages is not specified in the standard, so why expect a pause? No of course there isn't!
Not able to find a schematic? hard to believe. If I type "midi interface schematic" into Altavista, the first link contains many examples (the first of which already looks OK to me: http://home.concepts-ict.nl/~nctnico/...m_midi.gif. Based on that example, it should be a cinch to build your own.
If you need an example of a software implementation of a MIDI receiver, I will gladly send you one.
Beware! There are some pitfalls when interpreting incoming MIDI data, but most documentation on the web I've seen totally ignore them. So if your understanding of MIDI comes from (usually dodgy) web based info, read a few good books about MIDI first!