Indians in the Amazon still make ipé self bows. So it can be done. Just remember they use logs, and not milled boards... You need exceptionally straight grain, which is problematic to read in ipé. Also, the bow is kept LONG. These Amazonian bows are not like short American style hunting bows at all. 76" or so, oval cross section, maybe 1˝" wide, bend through the handle. So if that chap wants you to make a 64" elk hunting bow with a stiff handle, I'd just politely decline to make such thing myself.