In terms of female lines, probably the best you're going to get is the descendants of Helena Palaiologina, niece of Constantine XI. I happened to make an attempt in researching the most senior line of these a few years back; I'll quote the successor list, as far as I understood it, from my original research file (it starts when the normal Byzantine line dies out):
TOCCO
Leonardo I, titular Despot of Arta.............................ca.1519-1570
Costanza (fem).................................................1570->1591
(?)Francesco, co-lord of Refrancore............................>1591-1596
Leonardo II, titular Despot of Arta............................1596-1641
Antonio, titular Prince of Achaia..............................1641-1678
Carlo (Antonio), 3rd Prince of Montemiletto.....................1678-1701
Leonardo III, 4th Pr Montemiletto.............................1701-1776
Restaino, 5th Pr Montemiletto.................................1776-1796
Carlo II, 6th Pr Montemiletto..................................1796-1824
Francesco I or II, 7th Pr Montemiletto.........................1824-1877
Carlo III, 8th Pr Montemiletto..................................1877-1888
SERRA
Francesco II or III, 7th Duke of Cassano.......................1888-1917
Giuseppe, 8th D Cassano........................................1917-1918
Luigi I, 9th D Cassano.........................................1918-1935
Francesco III or IV, 10th D Cassano............................1935-1988
Luigi II, 11th Duke of Serra (Cassano?)........................1988-
[Note: I wouldn't advice assuming all of this is entirely correct!]
And as for
alleged (male-line) Palaiologos descendants,
this site gives a few paths that might or might not be real (some are apparently clearly erroneous at detailed inspection, some might be close to reality).
And then there's the Godscall Palaiologos story...