This is exactly what I had in mind! Thanks dariober! I edited the answer a little bit to just get the upstream bp (instead of a flanking region)
mysql -N --user=genome --host=genome-mysql.cse.ucsc.edu -A -e "select chrom, (txStart + 1) - 1000, (txStart + 1), name, name2, strand from hg19.refGene where strand = '+'" >proms_plus.bed
and
mysql -N --user=genome --host=genome-mysql.cse.ucsc.edu -A -e "select chrom, txEnd, txEnd+1000, name, name2, strand from hg19.refGene where strand = '-'" > proms_neg.bed