I haven't a clue, but if somebody does come up with an explanation for this character, I hope they would post it on http://www.decodeunicode.org/en/u+0243

Useful link, thank you cuttlefish!

Another source of information is the Unicode Code Charts. Enter U+0243 and then click "go". You get that U+0243 is the upper case of U+0180 for which one reads:

The official charts at unicode.org are usually pretty good at providing basic info on the relevance of a character. For instance, this page with some cross-referencing tells us Ƀ is a capitalized alternate symbol for the voiced bilabial fricative in Americanist phonetic notation.

Thank you, it is clever now.
By the way, have a look at the @tokiwoki's app Unipasta. He just updated it with a direct link to the Decodeunicode character page.

The text file http://www.unicode.org/Public/UNIDATA/NamesList.txt is also very handy. With simple searches, you often get there all the information you need.