Take any DVD-ROM/CD-RW slimline SlotLoading optical Drive, usually costs less than $80, take a SlimCD-to-IDE adapter (less than $10) and a USB-to-IDE adapter (less than ($40) and mount it under your screen. If you want to make a Bezel or a FrontPanel (Aluminium) in order to cover it so that It will look nice, try
www.frontpanelexpress.com, they have a free CAD software, so that you can design the Frontpanel and order it! Will cost less than 30$. Hope that helps!