www.socibus.es operate two buses daily from Madrid Barajas to Sevilla Plaza das Armas as follows:
Dept: Madrid Barajas Airport: 21:15 Arrive Seville: 04:10
Dept: Madrid Barajas Airport: 23:15 Arrive Seville: 06:10
It also operates four daily services from Sevilla Plaza das Armas to Madrid Barajas as follows:
Dept: Seville: 01:00 Arr: Barajas: 07:35 Till 14/06/13
Dept: Seville:08:00 Arr: Barajas: 15:15 Till 31/12/12
Dept: Seville:10:30 Arr: Barajas: 17:05 Till 31/12/12
Dept: Seville:14:30 Arr: Barajas: 21:45 Till 31/12/12
Not expensive either: € 21:50.
I have used this service in the past. Its a bit of a long journey, but it does avoid messing around with public transport in Madrid.
