first thanks for sqlamp we are using it to implement a forum.
To support numchild (ho much child has a node) i've added numchild to youre code. While adding that pice of code i fixed some errors we had with Postgres and test.
In the attached file bench.txt is a results of a benchmark (test). I used SQLAlchemy 0.5.8 and 0.6.6 with Python2.4 and Python2.6 on Sqlite (file, memory), Postgres 8.4.6, MySQL 5.1.49 MYISAM. Ahh i used a MacBook Pro Ubuntu 10.10 64Bit Core2Duo 2,4GHz 4GB Ram to run this tests.
P.S. Sorry i just found now your public repo so i didn't used the fork function