The Necropolitan template (LM 114) changes a character's type from humanoid or monstrous humanoid to undead. It does very little else, except give +2 turn resistance. The most interesting thing about this rather bland template is the method by which it is made LA+0.

When a character receives the template he or she loses one level (as if by raise dead) which resets the character's experience point total to halfway through the previous level; then the character loses another 1000 experience points.

If a third level character (3000 xp) undergoes the ritual, he or she will drop to 2000 xp (halfway between 2nd and 3rd level) and then lose another 1000 xp. That is exactly the minimum xp for a 2nd level character. All in all, this is very much like the variant rules for Reducing Level Adjustments (also known as 'LA buyoff').
Quote Originally Posted by SRD
The character must pay an amount of XP equal to (his current ECL -1) × 1,000. This amount is immediately deducted from the character's XP total. The deduction should reduce the character's effective character level (ECL) by 1
The thing with the LA buyoff rules is that you can only benefit from them at specific levels. For LA+1 you have to pay the xp at 3rd level. If you read the Necropolitan's special rule as an alternative way of paying off a LA+1 template, however, you could pay off a LA+1 anytime. Just lose a level and then pay another 1ooo xp.

The thing I am having trouble figuring out is how to do this with larger LA's. I think that an LA of +2 would take two steps, one with a level + 1000 xp, the second with a level + 4000 xp. Similarly an LA+3 would require these plus a final step of a level + 7000 xp, and so on. (The amount of xp increasing by 3000 each time). Does this seem appropriate?

Being more than two levels behind the rest of the group seems suicidal to me, but you would get xp a lot faster (according to the tables in the DMG on p. 38) and so would quickly catch up.

Does anyone else have a different system of handling LA buyoff?