I wonder what kind of stereo options there are. Are these just on the fly spaced/coincident arrays?
Yes.
The miniature DPA 4099 cardioids, designed for on-instrument mounting, generally have integral clips specific to the instrument type and flexible goosenecks and are intended to be clipped directly to the instrument.
The miniature 4098 supercardioids are designed as hanging choir mics or podium mics and have a short goose-neck section without a clip. DPA sells those with stalks of various lengths + goose-necks at each end as well. The goose-neck helps in setting up various stereo configs, and make it easy to tweak angles, but you'll need to DIY the mounting system depending on what you want to do.
Those 4098 and 4099 are the two DPA miniature cardioids you would probably be most interested in. But keep in mind that they are intended for close-mounting and have a response tailored for that with reduced low frequency sensitivity to compensate for proximity effect, unlike the standard top quality DPA cardioids designed to be used a greater distance such as Moke's 4028s. The other miniature DPA directionals such as the 4080 and 4088 are I think headset specific, not sure what their response is but I think they are specifically tailored for vocal use at the cheek. Some digging at the DPA website should tell more.
Here's a TS thread on the 4098's I use-
http://taperssection.com/index.php?topic=163927.msg2052993#msg2052993Here's a photo of the 4098 in a Mid/Side setup with a Naiant X-8S bi-directional, from another thread with all kinds of weird mic configs and mounting schemes-
http://taperssection.com/index.php?topic=96009.msg2181505#msg2181505