HI I just pruchased myself a 46mm 2x teleconverter. Results are suprisingly alright. Vignetting will occur with anything less than maximum zoom, which is to be expected. Barrel distortion and CA is increased with the teleconverter but nothing a bit of PP can't get rid of. Here is the setup
Now here is the camera set at maximum optical zoom 60mm with no teleconverter. Shots all RAW converter and distortion corrected manually, CA removal via PT lens.
Here is the same image taken at maximum optical zoom with 2.0x 46mm thread teleconverter effectively giving 120mm
Now here are the close up crops 100% of centre and edge performance.
As we can see centre performance is excellent and there seems to be more detail than if taken without a telelconverter. Edge performance, falls pretty fast, and for any kind of quality here, post process cropping can be done to remove this.
Would be keen to see others comments and possible samples from experiences with other types of teleconverters on the LX3 or the D-Lux4.