If I plan on going 10 Arcane Scholar and 20 Sorc is there any reason for me to take the practiced spellcaster feat? Do I loose any spell progression by taking Arcane Scholar?

I've seen level 20 10 sorc/10 as builds on nwn2db.com which use the feat, but from what I've read you don't seem to loose any spell progression by going Arcane Scholar making practiced spellcaster useless right?

Thank You

No for both questions. ASoC gains spells per day and spells known the same as if you took a level in your base spellcasting class. So no need for Practiced Spellcaster.

Technically this shouldn't work; the Arcane Scholar has full caster progression so you lose nothing and practiced spellcaster will cap at your character level. However, the feat is actually bugged with prestige classes and will raise your caster level above your character level. This is exceedingly good, but to be clear it's a bug and not the intended effect of the feat.

Good site for builds, check out the nwn2wikia for the feat in question. Although Darvin has already answered your question, its good to know for future reference.