Just today received one great issue from Republic Serbska (Bosnia, Serbian part), it surprised me like with design, massage, history and importance!
Here is part of promotional text that are attached from official site of Poste Srpske, hope that this Authority will not be angry with me because copy right issue:
So clever move from this country that I didn't see same or near same move from many other countries in last period! Here we have some topical that can be mentioned, like "stamp on stamp", "cheese", "olive", "building" and some more - it is also nicely designed, arranged and printed - in description it is also very educated from philatelist point of view - I never know this fact about perforation for this stamp - that it is in use just in monastery - someone know it?
Now, how much it will be rare we can just imagine, because hardly that all collectors will have it in mind and know about this issue, and rarity is connected on demand vs availability, but small quantity printed will have an impact, it is just 15 000 pcs printed - I think, most will be delivered to subscribers, and very small quantity will be used on regular mail - because that - if You can obtain it on cover - keep it in Your possession and track the market - You will find very good surprise I think!