[NiteWave]

standard version has 150 concurrent connections limit
for VPS license the limit is 500
for other license, no connection limit.

more detail info can be found here:
http://www.litespeedtech.com/litespe...-editions.html

your question:
can litespeed handle 50k -- 100k concurrent connections ?

while it looks hard to answer, try
1) litespeed itself may not be the bottleneck
2)assume 100k, and your NIC is 1G, then every connection only 10 bits/seconds or 1 bytes/sec. considering lots of TCP/IP overhead, should be less 1 bytes/sec per connection. all the users will feel too slow and quit ...