If you specifically want a warmer tone but don't want to buy an expensive vintage mic, you might try an ElectroVoice RE-20. I use it on my voice a lot and, since it is dynamic, you can also use it on guitar cabs and other sources if you like. I recommend you borrow one before buying.
I am sure you know this, but opening the trim/input sensitivity too much or failing to pad the mic enough can result in a harsh tone. This is a balancing act because I always want to get enough signal without getting the mic too hot. Do you use the -10db switch on the SE X1?
Interesting comments here from Sound on Sound:
"...with the X1 sounding more airy at the high end — so it has clearly had a ‘bump’ engineered into the upper part of its frequency response. This will benefit singers whose voices lack definition, but it could also work against somebody with a naturally bright vocal character. SE haven’t carried the coloration too far, though, and with the gentle application of EQ it should be possible to achieve good results with a fairly wide range of voice types. (In my experience, there seems to be more leeway with male than female vocals, as the latter, for some reason, often seem to be much more microphone-critical.)"