Welcome!
And no to being mad for wanting an e28! I am so happy with my e28, it's a 528i and i use it daily. Would be nice to increase the e28 numbers here and in general, compared to the herd of e30's
I dont know what specific e28 you are looking for, but I am a gumtree addict and check religiously every day and im telling you they dont pop up often. This humble 520i has been the best one ive seen posted in quite some time, so just a heads up if you are keen its going for 35k (im sure you can bargain) and if its got full maintenance i would recommend it. Be wary bills can rack up on these things, something i found out with mine.
e28's are far more scarce than e12's because we only got it 3 years into its life cycle, and they were only produced here for about 4,5 years
http://www.gumtree.co.za/cp-cars-in-randburg/bmw-e28-520i-465169692