Ellycat

[EllyCat]

I am looking for patterns for double bed sized crocheted canopy covers.

[Granny Square]

I 'haunt' vintage pattern sites regularly and have never seen a specific pattern for a bed canopy. 

Your best bet would be to modify a vintage thread lace tablecloth or bedspread pattern (one that was made with motifs would be easy to amend the size and shape).  Also, you could 'cheat' and buy a flat sheet the right size, hem it if necessary and and add a couple of rows of lace bed/tablecloth motifs, or find a wide lacy crochet edging or valance pattern to add around the sheet  (so only the lace would show unless you walked right up to the bed and looked up); back in the old days when canopies served a purpose canopies and bed curtains were solid fabric, so it would make sense to have a solid top. 

...After some more googling, I was assuming a flat top (parallel to the floor) canopy frame when I said the previous; if your canopy frame was not flat--look at this, this says it is thread lace bedspread used as a cover for a curved canopy frame.  And not cheap, but if this is hand made it is a bargain.

This site has a lot of copyright-free vintage patterns, link is to the main page, scroll down and look at bedspreads and tablecloths; some filet tablecloths have a wide separate pattern around the part that hangs off the table that might work if a solid sheet top is ok.

 

[MaryPat]

Years ago my bed had a canopy top.  I used a tablecloth pattern intended for thread but made it with a thicker yarn and a larger hook. 

Another time, I edged a rectangular piece of fabric with a pineapple tablecloth pattern.  If I recall correctly, I used a fingering weight yarn and a very large hook.  The rectangular piece of fabric was cut to the shape of the canopy -- I think it was a flat sheet originally.  The pineapple pattern was a from a rectangular tablecloth pattern.