Would arriving in Seville airport around 11h30pm be a problem? After customs and all...would it a be a sketchy to get in town and find a place to stay? Also, is it possible to rent a car in Seville and drop it off in Madrid a week later without big extra fees? Thank you

Picking up your car is no problem, provided your rental agency has your flight details. They will stay open. You should book your first night's accommodation in advance. Use www.booking.com for a vast selection and fair price. Most hotels have 24-hr reception. If you book with a national/multinational company, drop-off elsewhere in Spain is free. Try autoeurope or carjet.

I've no idea what "sketchy" means, but 11:30pm is not particularly late in Spain. I would email the hire car company to let them know you'll be arriving on this flight. I assume you're aware that Seville is not a car-friendly destination (at least not the narrow cobbled streets of the old town). I would make absolutely sure that I chose a hotel that has parking (and is easily accessible), and yes definitely book the hotel in advance.

do not even think of collecting a rental car and getting into Sevilla to LOOK for a hotel.
Book something in the historic section for one or two nights, and let a taxi take you. then when you are DONE with Sevilla and going to small towns, pick up your car IN TOWN or near the train station.

Taxis are fixed price to and from the airport, and it will more than compensate fro what you save on the parking, ( 18-20E/day) stress and one or two days rentals.

I think the question is very unclear, and the word unsketchy could well mean -- bad idea.

When you say to go into town at midnight to find a place to stay, do you mean you would not have any reservations? Or do you just mean finding your way to the hotel where you have a reservation? Seville isn't some small village, this plan sounds crazy to me. Forget the car while you are in Seville.

I'm please to introduce the word of the day "sketchy"; slang meaning wikipedia: 1) someone or something that just isnt right. 2) something unsafe 3) someone or something that gives off a bad feeling

Sounds like I should make a hotel reservation. Any recommendations for something an a budget? I will do the rental car only when I'm ready to get out of Seville. Taxi sounds like a reasonable idea to start. Thank you for the car rental web sites.

Seville taxis: just be careful not to get ripped off. We were charged 40 Euros for a ride from the airport to the old town, and I'm still cross with myself for falling for this blatant scam. Always agree the fare with the driver before you get in at the airport, especially late at night.

Taxi from 7 am til 9 pm should be around 20-21 euros, set fee. after that it goes up 25%, I think.