Wireless 3D Orientation Sensor Hardware

I please need wireless 3D orientation sensors built for prototyping the patent-pending project to first prove that certain application functions can operate as envisioned. I do not want any dedicated PCB design yet. If an already assembled prototyping hardware/firmware unit already exists that can work sufficiently, I will gladly pay a consultation fee for a capable recommendation of what unit(s) to use and why. I am all for the use of pre-built sensors initially, especially if they can help develop the project less expensively and/or more quickly. But for reasons I do not fully understand, some contractors seem to frown on them, claiming they are more complex and time consuming to work with and program in certain ways compared with constructing prototype hardware using more discrete components, boards or the like. So I am also open to the making of such prototype hardware, especially if I can understand why that might be better than a pre-built unit. One wireless sensor will be attached to the back of each hand (with something like just a band aid sufficient for now). While the most critical data needed first from each sensor is for helping to determine its 3D orientation, other types of available sensor data might ultimately be put to good use also so can be contemplated when choosing components. Accurate orientation values of each sensor/hand need to be independently measured and wirelessly sent/logged to another device. Measuring over the course of a golf swing will be a primary use, where higher capture rates can be nice but nothing should be needed beyond what today's standard components typically offer. An accurate clock somewhere is crucial, as the orientations of each sensor/hand need to be synced well with each other and compared mathematically and visually using elements of both 3D and 2D. Much passive analysis will take place with data recording and then playback. But there can also be good use for "real-time" operation so to speak. While orientation differences between the two sensors/hands relative to each other are most important, the ability to also provide absolute orientation values for each sensor/hand relative to some point of reference might be of good use for the application into the future. Sensor/hand orientations and their accuracies and stabilities are most critical, but being able to determine sensor movements/positions in space with precision and stability (without drifting issues) might eventually also be beneficial for the project. So this can also vaguely be contemplated in choosing a sensor and/or any other component(s), but not at the expense of orientation precision and stability, which remain most critical. Choosing components that might still be usable in future improved versions of the project/device would of course be nice. But depending on the cost of such components, keeping the device cost lower might be more crucial until certain basic application operations are proven successful first. The device should naturally be such that adding to and/or altering programming could be efficiently performed by a software contractor. While not very knowledgeable about specific hardware components and/or specifications, indicating which component(s) would be preferred and why might help me better decide what to do. Hourly or project rates can be considered. Please also approximate any additional costs of components, which I am not very familiar with. Several contractors have suggested that constructing at least four such devices would be prudent, two for a software contractor and two for me toward more efficiently developing further project software. Please let me know what other functional description(s) or other information I might be missing to help achieve the best prototype hardware. Thank you.