I've have been reading post all night with similar problems of the XML-sitemap timing out around 10,000 pages... and after reading all the post I am almost positive it is a problem with one of these parameters..."max_execution_time" , "max_input_time", "memory_limit". Unfortunately, my web host with godaddy will not allow me to change those parameters in the php.ini file. They gave me a php.ini file in the root directory, but it only has a couple parameters:
register_globals = off
allow_url_fopen = off
expose_php = Off
max_input_time = 5000
variables_order = "EGPCS"
extension_dir = ./
upload_tmp_dir = /tmp
precision = 12
SMTP = relay-hosting.secureserver.net
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=,fieldset="
Is there any way to get around this? Can I give you my account login in a personal message and have you take a look?