Can sudden metamagic feats (from Complete Arcane) be
used to scribe scrolls or craft wands that include the
metamagic effect? If so, how would you calculate the cost
(since sudden metamagic feats don’t alter the level of the
spell)?
You can use a sudden metamagic feat in item creation; the
cost to create the item would be just as if you were using the
regular metamagic feat. For instance, using your Sudden Widen
feat to create a scroll of widened fireball would cost as much as
a scroll of a 6th-level spell (which is what a widened fireball
is). The act of creating the scroll or wand would expend your
daily use of Sudden Widen (since the act of creation triggers
the spell, making it unavailable for casting).