
Volaran |
When given access to a Harrow Deck of Many things, the paladin in our group at the time (a scimitar-using follower of Sarenrae) drew the Paladin card, granting her a Holy Avenger. One of the other players drew The Forge and re-made the sword as a scimitar with the same powers.
Probably the most fortuitous combination of drawings from the Deck I've ever seen.

RuyanVe |

Greetings, fellow travellers.
There has been a similar thread floating around - asking whether a dwarven paladin could be granted an axe with the holy avenger "quality".
Consensus was, that there is nothing in the rules, which forbids or contradicts giving any other type of weapon the same gadgets as the iconical (and I think that's what it boils down to) holy avenger longsword.
Ruyan.

Sajuuk, Turtle of Creation |

The Holy Avenger power set is pretty much usable on any weapon. I've played a character in the past that got one as a Serren longbow (material from Book of Exalted Deeds, grants Ghost Touch to arrows fired from bows made of it).
Honestly, the only thing I WOULDN'T allow the Holy Avenger abilities to be added to would be a siege weapon. Unless it was crewed by a bunch of paladins.

Sajuuk, Turtle of Creation |

but yeah, it was always my opinion too that any enchantment either the holy avenger types or the flaming type could be on any weapon...
I wouldn't go so far as to say any pre-existing magic weapon could be re-weaponed into another type. One weapon I would stay away from doing that with would be the Scorpion Kama from Magic Item Compendium. Re-weaponing that can get pretty broken when you make it into a weapon with a high crit range.