yup,

I start bugging friends of mine who dj
And I know rekkid store owners personally, so
I bug them too... if that doesn't work.. I try
it on IRC

I can only speak of the dnb scene, but
we got a nice IRC scene on efnet
(#drumandbass, #junglemp3, #sour, #jungle)
and sometimes you can exchange records, on your
own risk though!

breakbeat.co.uk also got a buy/sell section
site (drum and bass only tho), this would be good
for ONLINEDJ.COM too by the way

and, KEEP LOOKING, one day you'll find it