Where can I buy the following records (from a place that has them in
stock / on hand):
Jan Johnston - Superstar (Bill Hamel Mix)
Highland - No Way Out (Highland Mix)

The Highland track you're after is available on a recording called
"Perfecto Presents Another World: Oakenfold", but unfortunately I've
only been able to find this on CD.

Greetings! As a trance fan and amatuer producer, I know finding the
right vinyls can be rough.  At the risk of sounding like an
advertisement, I'll refer you to Groovetech.com

Jan Johnston only recently released her own mixes, as she has been
doing vocals for such producers as Paul Oakenfold almost exclusively
for several years.  Groovetech currently offers her rendition of
"Flesh", a popular trance track; although I have been unable to locate
the specific mix you requested.  Hope this helps!

-Brendan