Finding a suitable Western Juniper log (out in the woods) like those pictured on my website is quite a bit more difficult than it may appear. I think the 2 most common uses for these are fireplace mantels and porch support columns. Most of the time I sell the fireplace mantels and juniper logs unfinished, the prices for these are located on my wholesale price list page.
To make the fireplace mantel I just cut (using my sawmill) the juniper log flat on the back and flat on the top, the rest of the work is done by the homeowner or furniture maker.

Juniper Mantel
If I do all of the work (usually for a homeowner) on the fireplace mantel, which includes the sanding and applying the finish, the cost is usually in the $120-$150 per foot range. If more than one fireplace mantel is purchased then I will work with you on the pricing.
Generally speaking, I like to sell 40 feet of fireplace mantels (give or take a few feet) at a time, you will get the best price per foot in this quantity. Fireplace mantels in the 6 foot range are the most common sizes, but I have made them up to 14 feet in length.

Juniper Columns - 20 Feet Long
Now for the columns, the most important thing about these is deciding whether they can be used in a load bearing application or not. The final decision for this should be made by a qualified architect. But, for load bearing applications the columns must be 100% solid. If they aren’t then don’t use them in a load bearing manner. Because of the character of the juniper trees that I search for is unusual, only about 1 in a 100 are solid, and it can be difficult to determine this just by looking at the tree, and there are quite a few factors I take into consideration before deciding to do any cutting.

Juniper Column - 20 Feet length