To be honest 5k is a difficult budget for this kind of car, too low for a decent W220 or E65 of any form, and personally I feel that 5k is too much spend on an E38 or X308 Jag, both of which look fairly dated now...however a Daimler Super V8 in the X308 shape may be a good choice if you seeking individuality on a 5k budget!
An early LS430 would be a reasonable choice and is likely to be less trouble than a 5k W220 but then again, the Lexus will lack the sense of occasion that I assume you are looking for considering the car is more of a toy than a necessity from what you describe. My advice would be to save up around 8k, enough for either a tidy w220, early 735 or 745 e65, or a reasonable x350 XJ.....
Bear in mind that any of these cars mentioned (Lexus or otherwise) can generate bills in the thousands just for fun, especially those models equipped with any kind of air suspension or electronic damper control so it would be wrong to base the reliability on brand alone, instead it would be prudent to carefully study the service history of each car you see individually and go for the one which appears to be have been cared for with no expense spared...If you are lucky enough to find such an example!