4 Tunna Brix runs about £10-£15 on eBay and is listed pretty often - you shouldn't have to wait more than a week or two to spot one. All Fall Down admittedly turns up less often, but who wants the 7" boot when you can have the Goofin' 12"?
Kali Yug is certainly tougher and typically runs to around £25-£40, but is hardly "impossible" to find - there was
one that ended yesterday with no bids...